Assisted power-up and hand-off system and method

ABSTRACT

The invention provides for an improved method and system of registration and hand-off procedures for a mobile node in a packet-based communication network. The present invention obtains expanded addresses over past systems. The invention can also use serving mobility managers to obtain a care-of address to route data-packets while on the foreign sub-network. The invention improves efficiency and reduces message overhead during registration and hand-off.

RELATED APPLICATION DATA

This application is the utility patent application related toprovisional application Ser. No. 60/238,899 filed Oct. 10, 2000.

TECHNICAL FIELD OF THE INVENTION

A power-up and hand-off communication protocol in a packet-basedcommunication system.

BACKGROUND OF THE INVENTION

Present-day Internet communications represent the synthesis of technicaldevelopments begun in the 1960s. During that time period, the DefenseDepartment developed a communication system to support communicationsbetween different United States military computer networks, and later asimilar system was used to support communications between researchcomputer networks at United States universities.

The Internet

The Internet, like so many other high tech developments, grew fromresearch originally performed by the United States Department ofDefense. In the 1960s, Defense Department officials wanted to connectdifferent types of military computer networks. These different computernetworks could not communicate with each other because they useddifferent types of operating systems or networking protocols.

While the Defense Department officials wanted a system that would permitcommunication between these different computer networks, they realizedthat a centralized interface system would be vulnerable to missileattack and sabotage. To avoid this vulnerability, the Defense Departmentrequired that the interface system be decentralized with no vulnerablefailure points.

The Defense Department developed an interface protocol for communicationbetween these different network computers. A few years later, theNational Science Foundation (NSF) wanted to connect different types ofcomputer networks located at research institutions across the country.The NSF adopted the Defense Department's interface protocol forcommunication between the research computer networks. Ultimately, thiscombination of research computer networks would form the foundation oftoday's Internet.

Internet Protocols

The Defense Department's interface protocol was called the InternetProtocol (IP) standard. The IP standard now supports communicationbetween computers and networks on the Internet. The IP standardidentifies the types of services to be provided to users and specifiesthe mechanisms needed to support these services. The IP standard alsodescribes the upper and lower system interfaces, defines the services tobe provided on these interfaces, and outlines the execution environmentfor services needed in this system.

A transmission protocol, called the Transmission Control Protocol (TCP),was developed to provide connection-oriented, end-to-end datatransmission between packet-switched computer networks. The combinationof TCP with IP (TCP/IP) forms a system or suite of protocols for datatransfer and communication between computers on the Internet. The TCP/IPstandard has become mandatory for use in most packet switching networksthat connect or have the potential for utilizing connectivity acrossnetworks or sub-network boundaries.

A computer operating on a network is assigned a unique physical addressunder the TCP/IP protocols. This is called an IP address. The IP addresscan include: (1) a network ID and number identifying a network, (2) asub-network IP number identifying a substructure on the network, and (3)a host IP number identifying a particular computer on the sub-network. Aheader data field in the information packet will include source anddestination addresses. The IP addressing scheme imposes a sensibleaddressing scheme that reflects the internal organization of the networkor sub-network.

A router is located on a network and is used to regulate thetransmission of information packets into and out of computer networksand sub-networks. A router interprets the logical address of aninformation packet and directs the information packet to its intendeddestination. Information packets addressed between computers on thesub-network do not pass through the router to the greater network, andas such, these sub-network information packets will not clutter thetransmission lines of the greater network. If data is addressed to acomputer outside the sub-network, the router forwards the data onto thegreater network.

The TCP/IP network includes protocols that define how routers willdetermine the transmission path for packets through the network. Routingdecisions are based upon information in the IP header and entries in arouting table maintained on the router. A routing table possessesinformation for a router to make a determination on whether to acceptthe communicated information packet on behalf of a destination computeror pass the information packet onto another router.

The routing table can be configured manually with routing table entriesor with a dynamic routing protocol. In a dynamic routing protocol,routers update routing information with periodic information packettransmissions to other routers on the network. The dynamic routingprotocol accommodates changing network topologies, network architecture,network structure, layout of routers, and interconnection between hostsand routers.

The IP-Based Mobility System

The Internet protocols were originally developed with an assumption thatInternet users would be connected to a single, fixed network. With theadvent of portable computers and cellular wireless communicationsystems, the movement of Internet users within a network and acrossnetwork boundaries has become common. Because of this highly mobileInternet usage, the implicit design assumption of the Internet protocolshas been violated.

In an IP-based mobile communication system, the mobile communicationdevice (e.g. cellular phone, pager, computer, etc.) can be called amobile node. Typically, a mobile node maintains connectivity to its homenetwork through a foreign network. The mobile node will always beassociated with its home networks for IP addressing purposes and willhave information routed to it by routers located on the home and foreignnetworks. The routers can be referred to by a number of names includingHome Agent, Home Mobility Manager, Home Location Register, ForeignAgent, Serving Mobility Manager, Visited Location Register, and VisitingServing Entity.

Authenticate, Authorize, and Accounting

In an IP-based mobile system, the mobile node maintains its connectivityto the home system through a foreign network. While coupled to a foreignnetwork, the mobile node will be assigned a temporary IP address, soinformation packets addressed to the mobile node can be routed to thetemporary EP address for the mobile node on the foreign network.

When a mobile node is operating on a foreign network, specializedservers are used to authenticate, authorize, and collect accountinginformation for services rendered to the mobile node. Thisauthentication, authorization, and accounting activity is called “AAA,”and AAA computer servers on the home and foreign network perform the AAAactivities.

Authentication is the process of proving one's claimed identity, andsecurity systems on a mobile IP network will often requireauthentication of the system user's identity before authorizing arequested activity. The AAA server authenticates the identity of anauthorized user and authorizes the mobile node's requested activity.Additionally, the AAA server performs the accounting functions bytracking usage on the network.

Functionally, a mobility manager will communicate with the AAA server inthe current domain, allocating another router to route informationpackets destined for a mobile node while it is located away from itshome sub-network. The mobility manager may have access to authenticationand key generation AAA functions to authenticate and generate sessionkeys. The mobility manager may also perform agent functions to forwardpackets to the mobile node until registration is completed.

IP Mobility Protocol

During the formative years since the Internet was first established,Internet Protocol version 4 (IPv4) was recognized and adopted as thestandard Internet protocol. With the advent of mobile IP andproliferation of computers and computer systems linked to the Internet,various limitations in the IPv4 standard and associated procedures havedeveloped and emerged. The most pressing limitation in IPv4 is therestriction on number of IP addresses. As shown in FIG. 1B, the addressfield size in an IPv4 packet is only 32 bits.

A number of benefits emerge from having a larger address field. First,there is little chance of exhausting the number of possible IPaddresses. Second, a large address field allows aggregation of manynetwork-prefix routers into a single network-prefix router. Finally,large addresses allow nodes to auto configure using simple mechanisms.More efficient system designs are thus possible with an expanded addressspace. Thus, there is a need for an IP standard with a larger IP addressspace.

In wireless IP networks and sub-networks (divisions of a network),mobile nodes can be physically located anywhere on the network orsub-network. Wireless IP networks handle the mobile nature of mobilenodes with power-up and hand-off procedures designed to inform themobile node's home network and sub-network of the location of the mobilenode for packet routing purposes. Because mobile nodes can move withinsub-networks and between networks, hand-off procedures need to beimplemented to insure that packets are continually routed to the mobilenode as it moves from one network to another or from one sub-network toanother.

Current protocols for obtaining a care-of address and procedures forpower-up registration and hand-off procedures are insufficient to handlecurrent packet-based communication demands. For example, the priorpower-up and hand-off protocols utilize system architecture that wasdesigned to operate within the constraints of IPv4's limited addressspace. These constraints are insufficient for supporting a standard thatneeds a larger address space and the associated network designarchitecture. Therefore, a need exists to establish a new user protocolfor power-up and hand-off procedures for mobile IP networks using anexpanded address space.

A new protocol for power-up and hand-off is also needed to satisfy thefollowing criteria:

1) Data transfer to a given mobile node should not be hampered by theintroduction of additional functional architecture,

2) The new protocol should require only minimal extensions and shouldexploit and track evolving routing and addressing capabilities,

3) The new protocol should be generic and independent of the type ofwireless technology or access medium,

4) The protocol should fully support and be consistent with an AAAarchitecture,

5) The new protocol should optimize air interface usage for efficiency,reducing the number of required overhand messages, such as BindingUpdate and Binding Acknowledgement messages, and

6) The protocol should also offer protection against over-use ormonopolization of resources by certain mobile nodes.

SUMMARY OF THE INVENTION

The present invention offers new methodologies or protocols forestablishing a communication link with a mobile node at power-up andmaintaining that link with hand-off procedures on or between networks.The invention uses care-of addressing located in an expanded addressfield in request and response messages. The invention also, at times,uses Dynamic Host Configuration Protocol (DHCP) servers and AAA computerservers to facilitate power-up registration and hand-off proceduresinvolving a mobile node. Using the DHCP server streamlines theprocedure, reducing packet transmission overhead and improving theefficiency of the system.

The first embodiment of the invention is called Intra-Domain Power-UpRegistration. This embodiment specifies registration message flow when amobile node powers-up in a foreign sub-network located on a home domain,sending registration message through a serving mobility manager (SMM) toa DHCP server.

The second embodiment is for Reactive Intra-Domain Hand-off, and thisembodiment is used when the mobile node is performing hand-off from asub-network to another sub-network within the home network. In thisembodiment, the mobile node has no forewarning of the move from onesub-network to another.

The third embodiment is a Proactive Intra-Domain Hand-off. Thisembodiment is used where the mobile node has knowledge that it will moveto a new sub-network, but the mobile node does not yet have a link layerconnectivity established with the new sub-network.

The fourth embodiment of the invention is the Inter-Domain Power-UpRegistration protocol, which is used when the mobile node powers up on aforeign domain. In this embodiment, the mobile node registers throughthe AAA server on the foreign network.

The fifth embodiment of the invention is the Reactive Inter-DomainHand-off protocol, which is used when the mobile node moves into a newforeign domain. The mobile node in this embodiment must use the AAAserver to register on the foreign network.

The sixth embodiment of the invention is the Proactive Inter-DomainHand-off and covers the situation where the mobile node is aware that itwill move to a new sub-network that is part of a foreign network, butthe mobile node does not have a link connectivity established with thenew foreign sub-network.

The present invention uses an expanded address format over IPv4, and isintended to reduce the amount of registration control, managementmessages (e.g. Request and Response messages), and information messages(e.g. Binding Update and Binding Acknowledgement). This invention willincrease efficiency of transmission and speed up the mobile IP systemsbecause it reduces the amount of overhead message transmission androuting.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the invention will become more readilyunderstood from the following detailed description and appended claimswhen read in conjunction with the accompanying drawings in which likenumerals represent elements and in which:

FIG. 1 is a communication network for the Intra-Domain Power-UpRegistration embodiment where a mobile node powers-up on a foreignsub-network of its home network;

FIG. 1A is the information packet format used in the present invention;

FIG. 1B is the prior art information packet format;

FIG. 2 is a message flow diagram for registration of the mobile node inthe embodiment of FIG. 1 for an Intra-Domain Power-Up Registration;

FIG. 3 is a communication network for the Reactive Intra-Domain Hand-offwith a mobile node moving from a sub-network, with no advance notice, toa foreign sub-network;

FIG. 4 is a message flow diagram for the Reactive Intra-Domain Hand-offfor a mobile node performing a hand-off in FIG. 2;

FIG. 5. is a communication network with a mobile node performing aProactive Intra-Domain Hand-off moving, with advance notice, from asub-network to a foreign sub-network on a home network;

FIG. 6 is a message flow diagram for a mobile performing a ReactiveIntra-Domain Hand-off in FIG. 5;

FIG. 7 shows a home communication and a foreign communication networkwith a mobile node powering up on the foreign network in an Inter-DomainPower-Up Registration;

FIG. 8 is a message flow diagram for an Inter-Domain Power-UpRegistration of the mobile node on the foreign network in FIG. 7;

FIG. 9 shows a home communication network and two foreign communicationnetworks, with a mobile node moving unexpectedly from one foreignnetwork to another and performing a Reactive Inter-Domain Hand-off;

FIG. 10 is a message flow diagram for the Reactive Intra-Domain Hand-offof the mobile node in FIG. 9;

FIG. 11 shows a home communication network and two foreign communicationnetworks, with a mobile node moving with advance notice from one foreignnetwork to the other and performing a Proactive Inter-Domain Hand-off;and

FIG. 12 is a message flow diagram for the Proactive Inter-DomainHand-off of the mobile node in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a Mobile Node (MN) 64 powering up on a foreign sub-network50 of a home network 100. The home network 100 has a central buss line54 coupled to a home AAA server (HAAA) 20 by communication link 55, aDHCPv6 server 30 coupled by communication link 56 to the buss line 54, ahome mobility manager (HMM) 40 coupled by communication link 17 to thebuss line 54, and a serving mobility manager (SMM) 10 coupled bycommunication link 15 to the buss line 54. The home sub-network 51 ofthe MN 64 consists of the HMM 40 coupled to the home agent 25 bycommunication link 19. The foreign sub-network 50 consists of the SMM10. MN 64 is linked to SMM 10 by a communication link 62, which may be awired or wireless connection.

In FIG. 1, the MN 64 is powering up on a foreign sub-network 50. FIG. 2shows the registration message flow for the situation where the MN 64powers up on a foreign sub-network within the home network. Thisembodiment is referred to as an Intra-Domain Power-Up Registration. TheMN 64 constructs a local IP address for use on the foreign sub-network50 by sending a Registration Request message (Reg Req) 105 to the SMM10. This Reg Req 105 is for allocation of a co-located, globallyroutable long-term IP address for the MN 64 while it remains on thecurrent sub-network 50. The Reg Req 105 also contains coincidentalinformation to verify the identity of the MN 64. The SMM 10 willvalidate the identity of the MN 64, and then send a DHCPv6 Requestmessage (DHCPv6 Req) 110 to the DHCPv6 server 30 requesting a newaddress for MN 64. The DHCPv6 server 30 allocates a new address to useas a care-of address and sends a DHCPv6 Reply message (DHCPv6 Rep) 115back to the SMM 10 with the new address. The SMM 10 relays this newaddress to the MN 64 with a Registration Response message (Reg Res) 120.The format of the IP header in the Registration Response message Reg Res120 is shown in FIG. 1A.

FIG. 1A shows the new information packet's IP header format with anexpanded address field. The Version (V) field 71 is a 4-bit long datafield that is used to designate the IP version number. The Priority (P)field 72 designates the desired delivery priority of the informationpacket. The Payload Length field (PL) 74 is the length of the rest ofthe packet following the IP header fields in octets. The Next Headerfield (NH) 76 identifies the type of header immediately following the IPheader fields. The Hop Limit field (HL) 75 is an 8-bit integer valuethat is decremented by 1 for each node that forwards the packet. TheSource Address field (SA) 77 is the 128-bit address of the source nodeof the information packet. The Destination Address field (DA) 78 is the128-bit address of the intended destination node. Various messageextension types, additional headers, and data fields can be found in thePayload fields (PLD) 79, the Reg Res 120 and Reg Req 105 being two ofthe possible types. The 128-bit care-of address will be in one of thesePLD fields 79 in Reg Res 120.

FIG. 1B shows the prior art IPv4 information packet's IP header format.The Version (V) field 81 is a 4-bit long field that is used to designatethe IP version number (version 4 in this case). The Internet HeaderLength field (IHL) 82 is 4-bits long and is the length of the IP headerin 32-bit words. The Type of Service (TOS) field 83 is 8-bits long andis an abstract indication of the quality of service desired. The TotalLength (TL) field 84 is 16-bits long and is the length of theinformation packet in octets.

The Identification field (ID) 85 is 16-bits long and is assigned by thesource node to aid in assembling fragments of an information packet atthe destination node. The Flag field (F) 86 is a 3-bit field withcontrol bit flags. The Fragment Offset field (FO) 87 is a 13-bit longfield that indicates where the information packet belongs in amultiple-packet message. The Time-to-Live (TTL) field 88 is an 8-bitlong field that indicates the maximum time the information packet willbe allowed to exist in the system before deletion. The time unitindicated is seconds. The Protocol field (P) 89 will indicate the nextprotocol level used in the Payload portion (PLD) 95 used in theinformation packet. The header Checksum field (CS) 90 is used to verifythe information packet.

The Source Address field (SA) 91 is a 32-bit field identifying thesource of the information packet. The Destination Address field (DA) 92is a 32-bit field identifying the intended destination of theinformation packet. The Payload fields (PLD) 93 are found after the IPheader and include various message extensions, additional headers, anddata fields. Compared to the IPv4 address fields, which include possiblecare-of addresses, the new message format shown in FIG. 1A offersaddress fields four times larger than found in IPv4.

The new address allocated by Reg Res 120 is used by the MN 64 as thecare-of address for routing data packet while it remains on the foreignsub-network 50. After receiving the allocated new address, the MN 64sends a Binding Update (BU) message 125 to the HMM 40 on the homesub-network 51. The HMM: 40 may allocate a router, HA 25, to providerouting and other services to the MN 64. If the HMM 40 allocates HA 25,a Binding Update (BU) message 130 is transmitted to HA 25. The allocatedHA 25 registers the MN 64 and responds with a Binding Acknowledgement(BA) message 135 to the HMM 40. The HMM 40 will transmit a BindingAcknowledgement (BA) message 140 back to MN 64 confirming receipt of theBU 125 and binding.

FIG. 3 depicts the situation where a mobile node moves unexpectedly fromone sub-network 281 to another sub-network 280 within a home network 300and must perform a hand-off routine. The embodiment to handle thissituation is referred to as a Reactive Intra-Domain Hand-off. FIG. 3shows a MN 264 linked to a transceiver 260 by a communication link 266.The transceiver 260 is linked to a sub-network 280 on network 300 vianew SMM (nSMM) 210 by communication link 259. Although this link to thenetwork 300 is a wireless connection, alternatively the connection couldbe a wired connection linking the MN 264 to the nSMM 210. Thesub-network 280 consists of nSMM 210, and it is a foreign sub-network280 for the MN 64 on the home network 300. The nSMM 210 is linked to acentral buss line 254 by communication link 215. A home AAA server(HAAA) 220 is coupled to the buss line 254 by communication link 255,and a DHCPv6 server 230 is coupled to buss line 254 by communicationlink 256. The old SMM (oSMM) 212 is coupled to the buss line 254 bycommunication link 216. A home agent (HAn) 226 is connected to oSMM 212by communication link 263. The oSMM 212 and HAn 226 form another foreignsub-network 281 on the home network 300.

A HMM 240 is coupled to the buss line 254 by communication link 217, anda home agent (HAm) 225 is coupled to HMM 240 by communication link 219.The HMM 240 and HAn 225 are the MN 64's home sub-network 282 on the homenetwork 300. The network 300 is linked to the Internet 235 bycommunication link 271 connected to central buss line 254. Acorrespondence node (CN) 274 is also linked to the Internet 235 bycommunication link 272, which may be a wired or wireless link. MN 264′is the prior location of MN 264, which is shifting connection on network300 as shown.

In FIG. 3, the MN 264′ is shown connected to the foreign sub-network 281and is moving unexpectedly from an area covered by oSMM 212 on foreignsub-network 280 to an area covered by nSMM 210 on foreign sub-network281. FIG. 4 shows the message flow for this embodiment where MN 264 isperforming hand-off from one foreign sub-network 281 to another foreignsub-network 280 within a home network 300 without prior notice. This newembodiment is referred to as a Reactive Intra-Domain Hand-off.

In FIG. 4, the MN 264 constructs a local IP address for use on theforeign sub-network by sending a Reg Req message 305 to the nSMM 210.The Reg Req 305 is for allocation of a globally routable IP address forMN 264 to use on the current sub-network 280. The format of the IPheader for Reg Req 305 is the same as shown in FIG. 1A. The MN 264 willalso provide coincidental information to verify its identity in the RegReq 305. The nSMM 210 verifies the identity of the MN 264 and thentransmits a DHCPv6 Req 310 to the DHCPv6 server 230 requestingallocation of an IP address. The DHCPv6 server 230 allocates a care-ofaddress and transmits a DHCPv6 Res 315 back to the nSMM 210 with thecare-of address. The nSMM 210 then transmits a Reg Res message 320containing the allocated new address.

After forwarding the Reg Res 320 to the MN 264, the nSMM 210 transmits aSystem Hand-off and Context Request message (SHC Req) 325 to the oSMM212. Upon receiving the SHC Req 325, the oSMM 212 will task HAn 226 toforward information packets from the previous care-of address to the newcare-of address (e.g. the new address allocated by DHCPv6 server 230).To task HAn 226, the oSMM 210 sends a Binding Update message (BU) 330 toHAn 226 along the same link the previous care-of address is located on.The HAn 226 responds with a Binding Acknowledgement message (BA) 335.The oSMM 212 then sends a System Hand-off and Context Reply (SHC Rep)340 back to nSMM 210 providing user context data, which is composed ofinformation such as session keys for the type of services granted.

After being assigned a care-of address in the Reg Res 320 and receivingcontext data, the MN 264 sends a BU 345 to the HMM 240, which includes alist of all IP addresses of all correspondent nodes the MN 264 iscommunicating with (e.g. CN 274). When the HMM 240 receives the BU 345,it allocates a home agent—HAm 225—to serve the MN 264, and sends a BU350 to bind the designated HAm 225. The HAm 225 processes and validatesthe BU 350. After completing processing of the BU 350, the HAm 225 sendsa BA 355 to the HMM 240.

Upon receipt of the BA 355, the HMM 240 sends a BA 360 to the MN 264,and the HMM 240 updates all the correspondence nodes listed by the MN264 in the BU 345 (e.g. CN 274) with the care-of address. This isaccomplished by sending a BU 365 to CN 274 (and any other node), whichwill reply with a BA 370. After a specified period of time to allowforwarding of all messages, the allocation of HAn 226 expires, becauseall future messages are forwarded to the care-of address and/or the HAm225.

FIG. 5 depicts a MN 464 linked to a foreign sub-network 481 on its homenetwork 500. The MN 464 is aware it will move to a new foreignsub-network 480, which consist of an nSMM 410, but the MN 464 does notyet have a link layer connectivity established with the new sub-network480. The home network 500 consists of a HAAA server 420, a DHCPv6 server430, nSMM 410, a HMM 440, a HAm 425, an oSMM 412, and a HAn 426.

The MN 464 is connected to a transceiver 460 by wireless link 466. Thetransceiver 460 is connected to the oSMM 412 by communication link 459.Although this communication link from the MN 464 to the oSMM 416includes a wireless connection, this link could alternatively be a wiredconnection linking MN 264 to oSMM 412. The oSMM 412 is coupled to a HAn426 by communication link 463 and to bus line 454 by communication link416. Foreign sub-network 481 consists of oSMM 412 and HAn 426.

The DHCPv6 server 430 is connected to buss line 454 by communicationlink 456. The HAAA 420 is connected to buss line 454 by communicationlink 455. The HMM 440 is connected to buss line 454 by communicationlink 417. HMM 440 is also connected to HAm 425 by communication link419. Home sub-network 482 consists of nHMM 440 and HAm 425. The nSMM 410is connected to the buss line 454 by communication link 415, and foreignsub-network 480 consists of nSMM 410. The home network 500 is connectedto the Internet 435 by communication link 471 to buss line 454.Correspondence node (CN) 474 is connected to the Internet 435 bycommunication link 472, which may or may not include a wireless link.The MN 464′ connected to nSMM 410 is the future location of MN 464.

FIG. 6 shows the message flow for the embodiment in FIG. 5, referred toas a Proactive Intra-Domain Hand-off. When the MN 464 detects that itwill move to new sub-network 480 on the home network 500, it sends aSystem Hand-off Request message (SHO Req) 505 to the oSMM 412, thecurrent serving mobility manager on sub-network 481. The format of EPheader for SHO Req 505 is the same as shown in FIG. 1A. The oSMM 412transmits a Hand-off and Context Transfer Request message (HCT Req) 510to the nSMM 410 on the sub-network 480, the future serving mobilitymanager. The nSMM 410 sends a DHCPv6 Req 515 to the DHCPv6 430requesting a new address to allocate as a care-of address. The DHCPv6430 transmits the care-of address to the nSMM 410 in a DHCPv6 Res 520.

The nSMM 410 transmits a Hand-off and Context Transfer Response (HCTRes) 525 allocating a care-of address to the oSMM 412. The oSMM 412allocates HAn 426 to bi-cast the data destined to MN 464 to both the oldand new care-of address. To accomplish this, a BU 530 is transmittedfrom the oSMM 412 to HAn 426, which will respond with a BA 535 to oSMM412. The oSMM 412 will then send a System Hand-off Response message (SHORes) 540 to confirm execution of the hand-off procedures and transmitthe allocated care-of address to MN 464.

After the MN 464 receives SHO Res 540 from oSMM 412 and establishes aLayer-2 connectivity with the nSMM 410 on new sub-network 480, it willsend BU 545 to HMM 440 to update the current binding on the homesub-network 482 with the new care-of address. The HMM 440 will updatethe binding to HAm 425 by sending a BU 550 to HAm 425, which in turnwill transmit a BA 555 to the HMM 440. The HMM 440 will transmit a BA560 to the MN 440 acknowledging the BU 545. The HMM 440 will also updatethe binding on CN 474 with the care-of address by transmitting a BU 565to the CN 474, and the CN 474 will acknowledge with a BA 570. If the MN464 does not receive a SHO Res 540 from oSMM 412 because it has Layer-2disconnection with the current foreign sub-network 481, the MN 464 willinitiate the Reactive Intra-Domain Hand-off protocol.

FIG. 7 shows MN 664 powering up on a foreign network 700. The MN 664 isconnected to the foreign network 700 by communication link 659. Theforeign network 700 includes the FAAA 621, the DHCPv6 631, and the nSMM610. The communication link 659 can be a wired or wireless connection.Communication link 659 is connected to the nSMM 610. The nSMM 610 iscoupled to a buss line 653 by communication link 615. The foreign AAAserver (FAAA) 621 is coupled to the buss line 653 by communication link652, and the DHCPv6 server 631 is coupled to the buss line 653 bycommunication link 633.

The foreign network 700 is coupled to the Internet 670 by communicationlink 673, which is coupled to buss line 653. The Internet 670 is coupledto the home network 699 by communication link 671, which is connected tobuss line 654.

The home network 699 includes the HAAA 620, the HMM 640, and the HAm625. A home AAA (HAAA) server 620 is coupled to buss line 654 bycommunication link 656. A HMM 640 is connected to buss line 654 bycommunication link 617, and HMM 640 is connected to HAm 625 bycommunication link 619.

When the MN 664 powers up on foreign network 700, FIG. 8 shows themessage flow under the new embodiment. This embodiment is referred to asan Inter-Domain Power Up Registration. The MN 664 sends a Reg Req 705 tothe nSMM 610 on the foreign sub-network 700 to obtain a co-located,globally routable address. The format of the IP header for Reg Req 705is the same as shown in FIG. 1A. The nSMM 610 validates the identity ofthe MN 664 using coincidental information in the Reg Req 705. Aftervalidation, the nSMM 610 transmits a DHCPv6 Req 710 to the DHCPv6 server631. The DHCPv6 server 631 allocates a co-located IP address to use as acare-of address and sends a DHCPv6 Res 715 back to the nSMM 610 with thenew care-of address.

At this point, the nSMM 610 may generate and transmit an optional IPOffer message 720 to the MN 664 containing the care-of address fortemporary use while registration is completed. The nSMM 610 willgenerate and transmit an AAA Registration and Authentication Requestmessage (AAA Reg Req) 725 to the FAAA 621. The FAAA 621 receives the AAAReg Req 725 and forwards an AAA Registration and Authentication Responsemessage (AAA Reg Res) 730 to the HAAA 620 based on the network accessidentifier extension (NAI) contained in the AAA Reg Req 725.

When the HAAA 620 receives an AAA Reg Req 730, it authenticates theidentification and authorization of the MN 664. If the MN 664authentication and authorization are affirmative, the HAAA 620 forwardsthe AAA Reg Req 735 to the HMM 640. The HMM 640 will process the AAA RegReq 735. If the MN 664 lacks a home IP address, the MN 664 will haverequested allocation of one. If requested, the HMM 640 will allocate ahome IP address for the MN 664. If the home network 699 is provisionedwith multiple home agents for load distribution, the HMM 640 maydesignate HAn 625 to serve the MN 664. The HMM 640 will then constructan AAA Registration and Authentication Response message (AAA Reg Res)740 with this information on the designated HAn 625 and theauthentication data and transmit an AAA Reg Res 740 to the FAAA 620.

The HAAA 620 will transmit an AAA Reg Res message 745 to the FAAA 621,which will contain a care-of address for use by the MN 664 allocated bythe DHCPv6 sever 631 and any home IP address allocated by the HMM 640 aswell as affirmative confirmation of AAA. The FAAA 621 will transmit anAAA Reg Res 750 to nSMM 610, and the nSMM 610 will generate and transmita Reg Res 755 to the MN 664 containing the allocated care-of address andany home IP address. Once the MN 664 receives the Reg Res 755, it sendsa BU 760 to the HMM 640 or any assigned HAm 625. The HMM 640 or HAm 625will then respond with a BA 765, completing the registration.

FIG. 9 depicts the situation where a MN 864 has moved and does ahand-off from one foreign network 899 to a new foreign network 900. FIG.9 shows three networks 898, 899, and 900. The old foreign network 899has an old FAAA server (oFAAA) 845, an old SMM (oSMM) 810, and a foreignagent (FA) 830. The new foreign network 900 has a new FAAA server(nFAAA) 850, a DHCPv6 server 860, and a new SMM (nSMM) 815. The homenetwork 898 has a home AAA server (HAAA) 840, a home mobility manager(HMM) 820, and a home agent (HA) 825.

On the old foreign network 899, the FA 830 is connected to the oSMM 810by communication link 831. The oSMM 810 is connected to a central bussline 877 by communication link 811, and the oFAAA 845 is connected tothe central buss line 877 by communication link 812. Although a wirelessconnection is shown linking MN 864 to nSMM 815, alternatively the linkconnecting MN 864 to nSMM 815 could be a wired connection.

On the new foreign network 900, the MN 864 is connected to transceiver860 by wireless link 866. The transceiver 860 is connected to the nSMM815 by communication link 859, and the nSMM 815 is connected to centralbuss line 871 by communication link 817. The central buss line 871 isconnected to nFAAA 850 by communication link 821 and to DHCPv6 server860 by communication link 819. On the home network 898, the HAAA 840 iscoupled to a central buss line 873 by communication link 841. The HMM820 is connected to the central buss line 873 by communication link 823,and the HA 825 is connected to the HMM 820 by communication link 827.

The three networks, 898, 899, and 900 are also connected to the Internet870. The old foreign network 899 is connected to the Internet 870 bycommunication link 881, which is coupled to the central buss line 877.The new foreign network 900 is connected to the Internet 870 bycommunication link 883, which is coupled to the central buss line 871.The home network 898 is connected to the Internet 870 by communicationlink 882, which is coupled to central buss line 873. MN 864′ is shownmoving from a location connected to oSMM 810 to a new location connectedto nSMM 815.

FIG. 10 depicts the message flow for the embodiment where the MN 864moves unexpectedly from one foreign network 899 to another foreignnetwork 900 and performs a hand-off. This embodiment is referred to as aReactive Inter-Domain Hand-off. The MN 864 sends a Reg Req 905 to thenSMM 815 to obtain a co-located, globally routable address. The formatof the EP header for the Reg Req 905 is the same as shown in FIG. 1A.The nSMM 815 validates the identity of the MN 864, and then transmits aDHCPv6 Req 910 to the DHCPv6 server 860. The DHCPv6 server 860 allocatesa new address to use as a care-of address and sends a DHCPv6 Res 915back to the nSMM 815. At this point, an optional IP Offer message 920containing the care-of address for temporary use until the registrationprocess is complete may be sent to the MN 864 by nSMM 815. The nSMM 815sends an AAA System Hand-off and Context Request message (AAA SHC Req)925 to oSMM 810 to allocate an agent, FA 830, in the old foreign network899.

The oSMM 810 will allocate FA 830 to forward information packets to theMN 860 by generating and transmitting a BU 930 to the FA 830. This willcause the FA 830 to forward information packets from the old care-ofaddress to the new care-of address. This binding will last untilregistration is complete and then expire. The FA 830 will respond with aBA 935 back to the oSMM 810 acknowledging the BU 930.

The oSMM 810 will verify the AAA SHC Req 925 by sending an AAA SystemHand-off and Context Response message (AAA SHC Res) 940 to the nSMM 815.The nSMM 815 will verify the message and allocate a co-located care-ofaddress for the MN 864, which it will transmit to the MN 864. The nSMM815 will generate and transmit an AAA Registration and AuthorizationRequest message (AAA Reg Req) 945 to the nFAAA 850, which forwards themessage to the HAAA 840 based on the network access identifier (NAI)extension in the MN 864 Reg Req 905.

When the HAAA 840 receives the AAA Reg Req 945, it authenticates theidentification and authorization of the MN 864. If the MN 864authentication and authorization are affirmative, the HAAA 840 forwardsan AAA Reg Req 950 to the HMM 820. The HMM 820 will process the AAA RegReq 950. If the MN 864 lacks a home IP address, the MN 664 will haverequested allocation of one. If requested, the HMM 820 will allocate ahome IP address for the MN 864. If the home network 699 supports morethan one HA 825 for load distribution and balancing, the HMM 820 maydesignate a HA 825 to serve the MN 864.

The HMM 820 will construct an AAA Registration and AuthorizationResponse (AAA Reg Res) 955 with this information on the designated HA825 and the authentication data and transmit the message back throughthe HAAA 840 and nFAAA 850 to nSMM 815. The HAAA 840 will forward theAAA Reg Res 960 to nSMM 815. The nSMM 815 will generate and transmit aReg Res 965 to the MN 864 containing the allocated, co-located care-ofaddress, any home address for the MN 864, and confirmation ofauthorization and authentication. After receiving the Reg Res 965, theMN 864 completes the registration by sending a BU 970 to the HMM 820 orany assigned HA 825, which will acknowledge with a BA 975.

FIG. 11 shows an embodiment where MN 1064 is aware of moving prior tomoving from old foreign network 999 to new foreign network 1000 andrequests a hand-off prior to moving. FIG. 11 shows three networks 998,999, 1000. The old foreign network 999 includes an oFAAA 1045, an oSMM1010, and a FA 1030. The new foreign network 1000 has an nFAAA 1050, aDHCPv6 server 1060, and an nSMM 1015. The home network 998 has a HAAA1040, a HMM 1020, and a HA 1025.

On the old foreign network 999, the FA 1030 is connected to the oSMM1010 by communication link 1031. The oSMM 1010 is connected to a centralbuss line 1077 by communication link 1011, and the oFAAA 1045 isconnected to the central line buss 1077 by communication link 1012. TheMN 1064 is connected to a transceiver 1060 by wireless link 1066, andthe transceiver 1060 is connected to the oSMM 1010 by communication link1059. Although a wireless link 1066 is shown, alternatively, MN 1064could be connected to the oSMM 1010 by a wired communication link.

On the new foreign network 1000, the nSMM 1015 is connected to a centralline buss 1071 by communication link 1017. The DHCPv6 1060 is connectedto the central buss line by communication link 1019, and an nFAAA 1050is connected to the central buss line 1071 by communication link 1021.

On the home network 998, the HAAA 1040 is coupled to a central buss line1073 by communication link 1041. The HMM 1020 is connected to thecentral buss line 1073 by communication link 1023, and the HA 1025 isconnected to the HMM 1020 by communication link 1027.

The three networks 998, 999, and 1000 are also connected to the Internet1070. The old foreign network 999 is connected to the Internet 1070 bycommunication link 1081, which is coupled to the central buss line 1077.The new foreign network 1000 is connected to the Internet 1070 bycommunication link 1083, which is coupled to the central buss line 1071.The home network 998 is connected to the Internet 1070 by communicationlink 1082, which is coupled to the central buss line 1073. The MN 1064′connected to nSMM 1015 is the location the MN 1064 is moving to.

FIG. 12 shows the message flow for the embodiment where the MN 1064lacks Layer-2 connectivity to a new foreign network 1000 it is aware itis moving to and performs a hand-off to move to the new foreign network1000. This embodiment is referred to as a Proactive Inter-DomainHand-off. The MN 1064 sends a System Hand-off Request message (SHO Req)1105 to the oSMM 1010 when it detects that it is moving to new foreignnetwork 1000. The format of the IP header for SHO Req 1105 is the sameas shown in FIG. 1A. The oSMM 1010 sends an AAA Hand-off and ContextTransfer Request message (AAA HCT Req) 1110 to the future nSMM 1015 viathe oFAAA 1045 on the old foreign network 999 and nFAAA 1050. The nSMM1015 transmits a DHCPv6 Req 1115 to the DHCPv6 1060 to obtain a newaddress to use as a care-of address. The DHCPv6 1060 allocates an EPaddress and sends a DHCPv6 Res 1120 back to the nSMM 1015 with a care-ofaddress. The nSMM 1015 then generates and transmits an AAA Hand-off andContext Transfer Response message (AAA HCT Res) 1125 to the oSMM 1010again via the nFAAA 1050 and oFAAA 1045 with the care-of address.

The oSMM 1010 allocates a FA 1030 to bi-cast data destined for the MN1064 to both the old and new care-of address by transmitting a BU 1130,and the FA 1030 will transmit a BA 1135 back to the oSMM 1010. The oSMM1010 will then send a System Hand-off Response message (SHO Res) 1140back to the MN 1064 to confirm executing the hand-off and transmittingthe co-located care-of address to the MN 1064.

When the MN 1064 receives the SHO Res 1140 from the oSMM 1010 andestablishes Layer 2 connectivity to the new foreign network 1000, itwill transmit a Reg Req 1145 to the nSMM 1015. The nSMM 1015 will thenconstruct and transmit an AAA Registration Request message (AAA Reg Req)1150 to the HAAA 1040 via nFAAA 1050. The HAAA 1040 will authenticatethe MN 1064. If the MN 1064 authentication and authorization isaffirmative, the request is forwarded to the HMM 1020 for furtherprocessing by an AAA Reg Req 1155.

The HMM 1020 updates the user state information, allocates HA 1025 toserve MN 1064, and constructs an AAA Registration Response message (AAAReg Res) 1160 to transmit to the HAAA 1040 conveying the data. When theHAAA 1040 receives the Reg Res 1160, it in turn generates and transmitsan AAA Reg Res 1165 to the nSMM 1015 via nFAAA 1050. The nSMM 1015 thensends a Reg Res 1170 to the MN 1064 conveying the information. Once theMN 1064 receives a Reg Res 1170, it proceeds to complete registration bysending a BU 1175 containing the care-of address to the HA 1025, whichacknowledges with a BA 1180.

As a further alternative embodiment in each of these embodiments themobility managers (SMM 10, HMM 40, nSMM 210, oSMM 212, HMM 240, nSMM410, oSMM 412, HMM 440, nSMM 610, HMM 640, oSMM 810, nSMM 815, HMM 820,oSMM 1010, nSMM 1015, and HMM 1020) may maintain a pool of addresses toallocate as care-of addresses to mobile nodes. If there is a pool ofaddresses to allocate, then the DHCPv6 Request messages (110, 310, 615,710, 910 and 1115) and the DHCPv6 Response message (115, 315, 620, 715,915, and 1120) are eliminated. In place of these messages (110, 115,310, 315, 615, 620, 710, 715, 910, 915, 1115, and 1120) the SMM 10, nSMM210, nSMM 410, nSMM 610, nSMM 815, and nSMM 1015 will periodicallyrequest a new pool of addresses from the DHCPv6 server to allocate ascare-of addresses.

While the invention has been particularly shown and described withrespect to preferred embodiments, it will be readily understood thatminor changes in the details of the invention may be made withoutdeparting from the spirit of the invention.

1. A method for registration of a mobile node on a packet-basedcommunication network comprising the steps of: requesting a care-offaddress for a mobile node by transmitting a request message to a firstnode on a first network, said first node capable of assigning a uniquecare-of addresses to each of a plurality of mobile nodes connecting tosaid first network; receiving a care-of address for said mobile node ata home network under a first circumstance from the first network,wherein said care-of address is an expanded address identifying thenetwork address location for said mobile node on the first network, andsaid care-of address is included in an information packet that comprisesa source address data field containing the expanded address for thesource node transmitting data in the information packet, a destinationaddress data field containing the expanded address for the intendeddestination node ultimately receiving the data, and a payload data fieldcontaining the data transmitted from the source node to the destinationnode; routing a message acknowledging receiving said care-of address tosaid first network; allocating a node on the home network to forwardinformation packets to the mobile node at the care-of address using abinding message transmitted on the first network to said node on thehome network; and updating a plurality of nodes with the mobile noderegistration address on the home network with said care-of address. 2.The method of registration of a mobile node on a packet-basedcommunication network of claim 1, further comprising the step ofrequesting said care-of address from a serving mobility manager on thefirst network.
 3. The method for registration of a mobile node on apacket-based communication network of claim 2 further comprising thestep of allocating said mobile node care-of address on the first networkafter said request step.
 4. The method for registration of a mobile nodeon a packet-based communication network of claim 3 wherein the care-ofaddress is transmitted through the serving mobility manager on the firstnetwork to said home network.
 5. The method for registration of a mobilenode on a packet-based communication network of claim 3 wherein thecare-of address is obtained from a pool of expanded addresses providedto said serving mobility manager on the first network.
 6. The method forregistration of a mobile node on a packet-based communication network ofclaim 2 wherein said first network is a foreign network and said firstcircumstance is a power-up performed by said mobile node on said foreignnetwork.
 7. The method for registration of a mobile node on apacket-based communication network of claim 2 wherein said first networkis a foreign sub-network located on said home network and said firstcircumstance is a power-up performed by said mobile node on said foreignsub-network.
 8. The method for registration of a mobile node on apacket-based communication network of claim 1 wherein the care-ofaddress is allocated by a server computer on said first network.
 9. Amethod of performing a mobile node hand-off on a packet-basedcommunication network, comprising the steps of: responding at a secondnetwork to a request for said mobile hand-off from a first network, saidresponse including allocating a care-of address, said care-of addresshaving an expanded address capable of identifying the network addresslocation for the mobile node on the first network, and said care-ofaddress is included in an information packet that comprises a sourceaddress data field containing the expanded address for the source nodetransmitting data in the information packet, a destination address datafield containing the expanded address for the intended destination nodeultimately receiving the data, and a payload data field containing thedata transmitted from the source node to the destination node;transmitting said care-of address from a serving mobility manager onsaid first network to the mobile node, said serving mobility managerfunctioning to request said care-of address from a first node on thefirst network capable of allocating a unique care-of address; allocatinga router on the home network to route information packets to said mobilenode at the care-of address using a binding message; and updating thecare-of address for the mobile node on a plurality of nodes on the firstnetwork and the home network.
 10. The method of performing a mobile nodehand-off on a packet-based communication network of claim 9 wherein thefirst node comprises a computer server.
 11. The method of performing amobile node hand-off on a packet-based communication network of claim 9wherein the first network is a first foreign sub-network on a homenetwork.
 12. The method of performing a mobile node hand-off on apacket-based communication network of claim 10 wherein the secondnetwork is a second foreign sub-network on a home network.
 13. Themethod of performing a mobile node hand-off on a packet-basedcommunication network of claim 9 wherein the first network is a firstforeign network.
 14. The method of performing a mobile node hand-off ona packet-based communication network of claim 13 wherein the secondnetwork is a second foreign network.
 15. The method of performing amobile node hand-off on a packet-based communication network of claim 9further comprising the step of moving the mobile node to said secondnetwork after requesting said mobile node hand-off.
 16. The method ofperforming a mobile node hand-off on a packet-based communicationnetwork of claim 9 further comprising the step of moving the mobile nodeto said second network before requesting said mobile node hand-off. 17.A method of registering a mobile node on a packet-based communicationnetwork comprising the steps of: transmitting a request message fromsaid mobile node to a first router that initiates assigning a care-ofaddress, said mobile node registering on a first network; receiving arequest from said first router at a server computer storing care-ofaddresses for allocating to registering mobile nodes on the firstnetwork; allocating the care-of address from said server computer, saidcare-of address having an expanded address for identifying a networkaddress location of said mobile node or other nodes, and said care-ofaddress included in an information packet transmitted over said firstnetwork comprising a source address data field containing the expandedaddress for the source node transmitting data in the information packet,a destination address data field containing the expanded address for theintended destination node ultimately receiving the data, and a payloaddata field containing the data transmitted from the source node to thedestination node; transmitting said care-of address to a servingmobility manager on a second network, said serving mobility managerallocating a router on the second network to provide routing and otherservices to the mobile node; and transmitting said care-of address tosaid allocated router and responding with a response message to saidmobile node indicating registering is complete.
 18. The method forregistering a mobile node on a packet-based communication network ofclaim 17 wherein the mobile node moves to the second network after thetransmission of the request message.
 19. The method of registering amobile node on a packet-based communication network of claim 17 whereinthe mobile node moves to the second network before the transmission ofthe request message.
 20. The method for registering a mobile node on apacket-based communication network of claim 17 wherein the care-ofaddress is transmitted through an AAA server computer on said firstnetwork.